Hatco IMPERIAL "S" - Manual (Page 35)

Form No. EBOOSTERM-0406 33
TROUBLESHOOTING
Temperature limit set too low.
Thermostat set too high.
Incoming water temperature
too high causing nuisance
tripping of high temperature
limit switch.
Loose connections or wire
connection has insulation
under crimp.
Low voltage.
Probe may be fouled.
Contactor(s) may be bad.
If booster heater is not overheating,
replace High Limit Safety Switch.
Adjust or recalibrate (page 27) to proper
temperature.
Incoming water temperature should
not be higher than 160°F (71°C).
Tighten all connections and check crimps.
Check control circuit voltage or secondary
voltage with transformer.
Bypass probe by removing wire from low
water cutoff probe and grounding to tank.
Clean or replace probe if chattering stops.
Test contactor coils. Replace contactor(s)
if bad.
SYMPTOM PROBABLE CAUSE CORRECTIVE ACTION
High temperature limit trips.
Chattering contactor or low
water cutoff circuit board.
WARNING
To avoid any injury or damage, the booster
heater must only be serviced by qualified
personnel.
WARNING
To avoid any injury or damage to the booster
heater turn the power OFF at the disconnect
switch/circuit breaker and allow to cool before
performing any maintenance.